Jacketed steam drier



P. E. oHLsoN ET Al. 2,677,899 JACKETED STEAM DRIER 2 Shetsr-Sheet l May1l, 1.954

Filed May 16, 1951 May 11, 1954 P. E. oHLsoN ET AL JACKETED STEAM DRIER2 sheets-sheet 2 Filed May 16, 1951 4. 1. I. .n i a IN VEN TOR5 Pda] E.'san EJWrJoa/ge BYf ATTORNEYS Patented May 11, 1954 tn.; Dei., assignpatetica Delaware Wilmiesien Applicationrmay is, 1951, ...serrati ivo.assises .11 CL: .34a-:13.9.:

The present invention relates to,steam ja0kelind. driers `of the typeused :in paper `mills, food processing plants, `industrial'Achemicalinanuf,acturing plants, andthe lik Driersofthe 4kind. which areimproved by the present nventionare to be .distinguished from heavy castv iran ldriers in..which the entire interiors. of the cylindrical'drurnsrare filled ,with steam, since jacketeddriers conventionally .have.their interiors open', tu .the atmosphere and comprise a pairofconcentric, steel cylinders, providing aclosed space. theref between,into .which relatively high.4 pressure steam is delivered,.and fromwhichlcondensateis removed.Y

A primaryobject ofthe present inventionis to provide. means. forincreasing the. rate of heat transfer .from the exterior surface .of a.steel jacketed 'drierto the material being dried. .i

"I'o this-end,-..an important objeotofnthe invente tion is to increase`the ,..velocityibsteam,.flott through the jacket space inthedrien Suchin? creased .velocityl of steam now. exerts. a scouring" action upon theinnerlsurface oi.. the outer cylin-n der.. and effectively. .preventsthe, formatiomota lrn or layer of condensate .n...said ..-surface,.which,. in conventional practice. acts as-ansin'f. sulating layer andreduces therate o.heat.trans. fer romthev steam .tothe cylinder. iThesconrng action', effected by. the improvements of thefpres;

ent inventioiralso. effectively removesairand: o

non-.condensable-.gasesfrom: .the .jacket space',A thereby.` 'furtherrate;

lt has been .standard .practice .in the: .j acketed" drier artto! spacethe. inner. and `outer`fcylindrs substantially two inches.' apart,lregardles's" of the diameter of. the drier, which lniay vary .from ,36:inches to 144" inches; Thisrelativelyilarge.jacket space results. innumerousnisadvantages Avvhiclfi have' not been appreciated or understood'inthe prior art. The velocity of steam llovv iLthe jacket .spaceisinsuicient -to eiiect the desifed scouring actiorard theremovalof`cndesatef air; and nonwon'densable gases. 'A'ccodingljeat low. speed,the condensate puddles badlynear the bottom v`ofl the. drier, therebyinterfering with? heat .transfer'and increasingthe power requiredtorotate the drier. ta high!' s'peed,` thecondensaterims'lin a filmaround the entire inner surface ofthe: outer cylinder and intereeSPWthheatv transfer. Air

venting. and low" rate' of stean'lw.-

No attempt inhthe past liasbeenmadeto conimproving. the (heat transfer..

h and nqn-condensable gases:4 remain in the jacket space because of-vsuch a manner as to. effectmaximum. heat transA fer... No` ,means have.been providedto eiect even and uniform distribution `of steamflojy over.theentire inner surfaceof the. drier.

The. purpose of the present invention .is to overs, come all of. .theforegoing defects; to ,produce a suiiciently .high velocity of steamow.to scour air, water, and .incondensablegases; to effect even `and/uniform distribution. `of A`steaniafiow4 withinA the-jacket space;A andto control thequality oi?` theisteam Within the jacket to effeCtmaXi.-mum.. heat transfer.

As. a, ,resultof shopexperimentation and theoretical calculationsit hasbeen determined that a steamifiow. .velocityupon. .theintroductiong ofthe steam into .the jacket. space, .of feetper minute. and a discharge.vvelocity vof-v lovvvi,qualityy steam and condensate .of` 7 feet perminute 4or more is necessary. toproduce the desired scouring action andtto. `eiiectvproper. removal ofcondensate, air,. and non-condensablegases.

The objects.of; the .present invention .are,..aci, complished',., asexplained, .in connection. .with .the illustrativev embodimentsdescribed .be1ow,.. by .decreasing the radial dimension .of the steam'space between the `outer. and .inner cylinders, .to sub.-U stantially34,' of an inch, more or` less, depending uponlthe diameter. fof. thedrier by. dividing: fthe jacket space intoa .pluralityof longitudinallyextending compartments steam atfhighl velocity. to. the compartment. atAla plurality.. of. .points 4through openings of accurately .determinedareas.; and by providing means foron .1315@ 3 0f Figure. 1.5

-Figure' 4 is an'V enlarged fragmentary section stearddelivey andc'nder'isatev rnovalninfstriif mentalities; and

Figure 5is' a` fragmentary axialvsection` on an enlarged sca-le'With'jcejtainpartls broken avvay.J

A parof' hollow journals' l (i andi I, v`intercnby .delivering theVleading ends ofthe y removing 10W quality steam and .condensate adjacentthe trailing ends of. the

nected by a central shaft I2 may be supported in conventional manner bysuitable bearings, represented diagrammatically at I3 and I4. Thejournals carry end plates or heads I5 and I6, which may have openings I1therein so that the interior of the drier is open to atmosphere. Securedto the outer margins of the two heads are a pair of inner and outersteel cylinders I8 and IS, disposed in closely spaced concentricrelation and spaced apart by end rings and 2I, to which they are welded,to provide a closed jacket space 22.

As indicated in Figure 5,the heads may be reinforced by radial webs 23,extending from the inner cylinder I8 to a supporting ring 24, secured tothe journal II in any appropriate manner, as by bolts extending througha flange 26 integral with or mounted upon the journal.

The space 22 between the inner and outer cylinders is divided into aplurality of longitudinally extending compartments, by a plurality ofstainless, spring steel vanes 3u, having their inner portions 3| weldedto the outer surface of the inner cylinder I8 and their outer edgeportions 32 bearing against the inner surface of the outer cylinder I9with spring pressure. As indicated by the arrows in Figures 2 and 4, theVanes are Apitched forwardly and outwardly in the direction of rotationof the drier. Moreover, they extend longitudinally in angular relationto axial sections of the cylinder so that condensate engaged by theirleading faces tends to iiow, under the influence of inertia, gravity,and centrifugal force, toward their trailing ends.

The inner cylinder I8 is provided with a plurality of rows of apertures33, one row being disposed adjacent the leading faces of each of thevanes 30, at the trailing end of each compartment in the space 22. Theseapertures provide means for the discharge of condensate, lowqualitysteam, air, and non-condensable gases from the several compartments; andsuch now is facilitated by the scooping action of the varies.

The inner cylinder I8 is also provided with a plurality of rows ofopenings 35, disposed in parallel relation to the apertures 33 with onerow positioned behind each vane and near the leading end of eachcompartment in the space 22. As hereinafter explained, steam fiowsthrough these openings into the several compartments. In order toprevent the direct impingement of the steam upon the inner surface ofthe outer cylinder, at points in alignment with the openings, and toeffect a uniform dispersal of the steam, the openings 35 are fitted withnipples 36, having closed, circular outer ends, constituting bales 31and laterally directed, slotted openings 38 and 39, so that the steam isdirected laterally, as distinguished from radially, into the jacketspace 22.

Upon the inner surface of the inner cylinder, in alignment with each rowof apertures .'23, there is an outwardly facing trough 40, consisting ofa U-shaped sheet metal strip welded to the cylinder I8 and disposedlongitudinally in angular relation to axial sections of the drier, inthe same manner as the vanes and the rows of apertures. Accordingly,condensate flowing inwardly through the apertures 33 into the troughstends to flow longitudinally toward the trailing ends of the troughs or,in other words, toward the left in Figure 1.

At the latter end, each trough is connected to a radial pipe 4I havingits inner end connected toan axial pipe 42, extending through the jour-4 nal II and bearing I4, to a suitable condensat collecting trap andreturn steam line, not shown.

Adjacent each trough 40 is a second trough 45, which may consist of anL-section sheet metal strip, welded to the U-section strip 40 and to theinner surface of the inner drum I8, as illustrated in Figure 4. Eachtrough 45 encloses the associated row of openings 35 and nipples 36. Atthe right hand or leading end, each trough 45 is in communication with aradial steam delivery pipe 46, extending into the interior 41 of theright hand journal I0, to which is connected a steam supply pipe 48.

In many cases, particularly where the length of the drier exceeds thecircumferential dimension, it'has been found highly advantageous todivide the space 22 into a plurality of separate compartments' bypositioning circumferential rings in the jacket space. For instance, theentire space may be divided into four compartments or chambers,longitudinally of the drum and each of these compartments again dividedby the fins or vanes 30. One circumferentially extending ring may bepositioned midway between the end rings 20 and 2|, and two othercircumferential rings midway between the first mentioned one and the endrings. Such an arrangement Vprevents a direct longitudinal flow from thesteam inlets to the outlets; results in a more uniform, circumferentialflow of steam 1n the several compartments, and provides an improved andmore thorough scouring action for the removal of air and non-condensablegases. This arrangement has been found to be of importance and toproduce highly advantageous results in elongated driers, such as thosehaving a 60-inch diameter and a 23S-inch length.

In the operation of the apparatus of the present invention, high qualitysteam at relatively high pressure, in the neighborhood of 125 pounds persquare inch is delivered through pipes 48 and 46 to the interior of thelongitudinally extending distributing troughs 45, from which it flowsthrough the nipples 36 into the several compartments, into which thespace 22 is divided by the vanes 30. The high quality steam isdistributed uniformly and evenly throughout the compartments vand givesup its latent heat to the outer cylinder I9, which results in areduction in the quality of the steam, considerable condensation on theinner surface of the outer drum, and a high velocity steam flow. The lowquality steam flows from the space 22, inwardly through apertures 33into the trough 40, with a relatively high velocity flow, which resultsin a scouring action within the space 22, tending to drive condensate,air, and non-condensable gases toward the trailing end of eachcompartment. The vanes 30 exert a scooping action on the condensate andforce it to flow through the apertures 33 into the trough 40.

Because of the angular disposition of the troughs 40, from end to end,the condensate, through the influence of centrifugal force, inertia, andgravity is caused to flow longitudinally in each trough toward thetrailing end thereof, where the condensate is received by the radialpipes 46 for flow through the interior of the journal II, and fordischarge through the pipe 42.

In order that the quality of the steam may be reduced from substantiallywhen it is introduced, to substantially 10%, when it is dischargedthrough the apertures 33, to produce a. high velocity flow and to giveup a major portion of its latent heat, it has been found that.

Y:minedi direction,

the. total crossiseotional .area of .ftheaportures Should equal;approximately 0f` thctotal crossesectional area of f. thel steam space22. Moreover, in -order that thev yeloctyof fthe .flow ofsteam .in thespaceibe high, the .radial ,dimension thereof shouldfbe small.-

Experiments and theoretical. Calculations have demonstrated that adrierirl accordance, with. .the present inventio c, using steam,pressures. of be.- twccn-125 and 18,0 poundsfper. Squareinohre.- Sultsinan increase-of heat transferof between 2.2%y and 2.9%.v215..;...00Innared withnriorstoam iaoketed. driers. operatingy .etsimilarpressure. but not provided with the improvements .of Ythe presentinvention..

Itfmust be.. understoodthat theinvention isfnpt limited` to Athe.detailsoitconstruction shown in tlicaccompanyine.drawingsanddescribed above, asVmany,modifications. will occur .to those skilled in theartifrom aconsideration of this ,disclosura f Theinvention includesallrmodiiications ycomme within thefscone of the. appended claimsand-:their equivalents.

We claim:

1- A.; drier comprising ari-air of concentric. closely spaced, inner andouter` cylinders ,mountdffor rotation in a predetermined direotionaridhayi-ngtheinteriorof the-,inner cylinder open to theatmosphere,eas-tightisealins moans closing the ends, of thespace between thecylinders, a

plurality. of vanosfcxtendine lorlsitudiiially from end to end ;of,.the-,cylinders .and dividing .the space therebetween into a. pluralityofi` longitudinal compartments, the innercylinder having a row ofopenings .behind ,each oil-said vanesand a row of-aprerturesaheadf eachvane, means for de liveringsteam througheach row-.off openings to saidcompartments adjacent the. lea-ding en-ds thereof and trough meansvcabried bythe inner Sur-face. of theinner-cylinder rtepisttiine'v withthe rows of aperturesfor collecting condensate and low quality steamiiowing through the apertures in the inner.. cylinder,

2. A drier comprisingy a. pair. oi.,- concentric, closely spaced inne'rand`outer steel cylinders of substantially equal wall'thickness mountedvfor rotation about their common axis` in adpredeter gas-tight sealingmeans closing the ends of the space between the cylind`ers,`a

plurality offvanes extending longitudinally lfrom y end to end ofthecylinders; dividing the space therebetween, into, al pluralityof.`longitudinally extending compartments, said vanes being. for.-wardlyandoutwardly pitched from thelinner to the outer cylinder,the`inner cylinder having a row of" openings behindv each of said vanesand a row of aperturesaheadof each. vane, means for delivering, bienquality irish pressure Steam throueneaonrow. of openings tothesaid Spaceand trough means carried by the inner surface of the inner cylinderregistering with the rows of apertures for collecting condensate and lowquality steam owing from said space through said apertures.,

3. A drier comprising a pair of concentric, closely spaced inner andouter steel cylinders of substantially equal wall thickness mounted forrotation about their common axis in a predetermined direction, gas-tightsealing means closing the ends of the space between the cylinders, aplurality of vanes extending longitudinally from end to end of thecylinders, dividing the space therebetween into a plurality oflongitudinally extending compartments, said vanes being secured to theouter surface of the inner cylinder ends thereof, the

and: projecting outwardly.. in. forwardly. pitched relation.v intoContact. with `the inner. surfacerof theouter .,cylinder, means jfor.delivering steam .t0 said vcompartments vbehindeach oifsaidI ,-vanes,said innercylinder haring a ,rowofapertures .adjacent the .leading faceofeach vane. for the in,- ward Aiiow .of :low` quaIitysteam yandcondensate. and a plurality of .trolls S 011 .the ,inner` surfa e of.the inner. cylinder registering with,` said :rows of. apertures` forcollecting the inwardlynowing condensate and flow lquality steam.

4. A. drier. comprising. av pair` of concentric, closely spaced innerand outerstcel, cylindersof substantially. equal wall-,thickness mountedfor rotation. abouttheir. common. ,axis` in a .predetcr mineddirection,gaseti htsealingmeans closing `the ,ends of the.. pacebetween ,thecylinders,v a plurality .of vanes extending longitudinally. vrfrom end..to` end of the `vcylinders dividing the, space therebetween. into, aplurality.. ofv longitudinally extending compartments, said vanesbengse.- cured`to the outer ,surface of .the inner cylinder andprojecting .outwardly in forwardly pitched re.- lationinto contact withthe innersurface of,-the outer 'cylinderl and; disposed longitudinally,in angular .relationlto axial sections ,ofv Vthe cylinders, wherebylongitudinal .flow is imparted ,fto,conden;,n sate engaging the vanes,ymeans. for. delivering steam to the compartmentsadjacent. the. leadinginner` cylinder having a row .of .aperturesadjacentthe trailing .end .oreach compartment opposite; the. .leading ,face of the asso,- elated.lvane for the inward now.. of condensate, andanoutwardly facingtroughsecured to, the

" inner surface ofthe inner cylinder, enclosing each .row of apertures`tcl-.receive said-condensate.

5.. A drierl comprising a pair of concentric, closely spacedinner. vandouter lsteel cylinders of substantially equal. wall thickness, mounted..for

their commonl axis, in. a. predetcimined direction, gas-tight. sealingmeansolos.- ing theends Iofithespace betweenthe cylinders, a pluralityof vanes extending longitudinally. from end to. end of'. the cylinders.dividing the. space therebetween.. intoa pluralityof longitudinallyextending. compartments, said vanes being. se.- lc uredto theoutersurface of the. inner. cylinder ksate engaging the vanes, means fordelivering steamto the compartments adjacent theleading ends thereof;the inner cylinder` having a. row. of apertures adjacent the trailingendl of each compartment opposite.` the leading face of the asso:-ciated vane for the inward flow of condensate, and an O utwardly facingtrough secured to. the innersurface ofthe inner cylinder,

the cylinders, whereby longitudinal flow is imparted to theconcondensate received Papertures of reduced total cross-sectional areaas compared to said openings extending through the inner cylinderadjacent the trailing end of each compartment, a plurality of pairs ofadjacent troughs extending longitudinally along the inner surface of theinner cylinder with one trough of each pair embracing the openings ofone compartment and the adjacent trough of each pair embracing theapertures of the compartment ahead thereof in the direction of rotationof the drier, means for delivering steam to the first trough and meansfor removing condensate from the second trough.

'7. A drier in accordance with claim 6 in which the means for dividingthe space between the cylinders into said compartments comprises aplurality of longitudinally extending varies se- -cured to the outersurface of the inner cylinder, vprojecting outwardly in forwardlypitched relation and contacting the inner surface of the outer cylinder.

8. A drier in accordance with claim 7 charac- `terized in that the vanesand the troughs are disposed in angular relation to axial sections ofthe cylinder, whereby longitudinal flow is imparted to condensateengaging the vanes and to in the second trough, said drier being furthercharacterized by the inclusion of means for removing condensate from thetrailing end of the second trough of each pair.

9. In a jacketed drier of the type having an open interior andconcentric inner and outer cylinders dening a closed annular' steamspace therebetween, a central shaft, journal means therefor, means fordelivering steam to said space through one journal and means forremoving condensate through the other journal, the improvement in thesteam delivery and condensate removal means which comprises a pluralityof forwardly and outwardly pitched vanes, secured to the outer surfaceof the inner cylinder making contact with the outer cylinder anddividing said space into a plurality of longitudinal compartments, a rowof openings extending through the inner cylinder behind each vane, a rowof apertures extending through the inner cylinder adjacent the leadingface of each vane, means for delivering steam to all of the openings, atrough on the inner surface of the inner cylinder enclosing each row ofapertures, and means connecting each trough to the condensate removalmeans extending through said other journal.

l0. In a jacketed drier of the type having an open interior andconcentric inner and outer cylinders dening a closed annular steam spacetherebetween, a central shaft, journal means therefor, means fordelivering steam to said space through one journal and means forremoving condensate through the other journal, the improvement in thesteam delivery and condensate removal means which comprises a pluralityof forwardly and outwardly pitched varies, secured to the outer surfaceof the inner cylinder making contact with the outer cylinder anddividing said space into a plurality of longitudinal compartments, a rowof openings extending through the inner cylinder behind each vane, a rowof apertures extending through the inner cylinder adjacent the leadingface of each vane, a trough on the inner surface of the inner cylinderenclosing each row of openings, and means connecting each trough to themeans for delivering steam through the rst mentioned journal.

11. In a jacketed drier of the type having an open interior andconcentric inner and outer cylinders defining a closed annular steamspace therebetween, a central shaft, journal means therefor, means fordelivering steam lto said space through one journal and means forremoving condensate through the other journal, the improvement in thesteam delivery and condensate removal means which comprises a pluralityof forwardly and outwardly pitched vanes, secured to the outer surfaceof the inner cylinder making contact with the outer cylinder anddividing said space into a plurality of longitudinal compartments, a rowof openings extending through the inner cylinder behind each vane, a rowof apertures extending through the inner cylinder adjacent the leadingface of each vane, a trough on the inner surface of the inner cylinderenclosing each row of openings, means connecting each trough to themeans for delivering steam through the first mentioned journal, a secondtrough positioned adjacent each of the rst mentioned troughs on theinner surface of the cylinder enclosing each row of apertures and meansconnecting each of the second mentioned troughs to the condensateremoval means extending through the second journal.

References Cited in the le of this patent UNITED STATES PATENTS OTHERREFERENCES Trade Journal, Industrial Development January 20, 1949, pages16 and 17.

Paper Section,

